Research on Reactive Power Coordination Control of Urban Rail Transit Power Monitoring System

[Objective] The power supply system of urban rail transit mainly relies on the SVG (static var generator) or reactors in the 110 kV main substation for centralized reactive power compensation. The current control mode does not fully consider the reactive power compensation capacity of the decentralized energy feedback devices, easily leading to problems such as long-term heavy-load operation of the SVG, over-compensation or under-compensation of the reactors. Therefore, it is necessary to incorporate the energy feedback devices into reactive power compensation and study the coordinated control method of the reactive power compensation equipment in the main substation and the energy feedback device, so as to solve the problem of reactive power coordinated control in the power supply system. [Method] A reactive power coordinated control method based on the central-level power monitoring system is proposed. With the SVG, reactors, and energy feedback devices introduced into the reactive power control objects, the real-time reactive power coordinated control is achieved through online control zoning, incoming line power factor control strategy, and economic voltage difference reactive power balance control strategy. [Result & Conclusion] The proposed real-time reactive power coordinated control method is to construct a reactive power coordinated control module in the central-level power monitoring system. According to the real-time data of the whole line and the power supply system model, online control zones are partitioned, and reactive power coordinated control is performed for each control zone. If the incoming line power factor is unqualified, the reactive power compensation amount is calculated according to the power factor control target and allocated to the reactive power control objects according to the allocation principle. If the power factor is qualified, the reactive power balance coordinated control should be carried out according to the economic voltage difference method. Through the above coordinated control methods, the objectives of reducing the compensation capacity of the SVG, meeting the inco-ming line power factor assessment, and reducing the active power loss of the power supply system can be achieved.